Our analysis of the combined effects of acute ethanolism and head trauma will continue in the coming year with scrutiny of changes in the autoregulation of cerebral blood flow. Alterations in total flows have been followed but we have no data on regional blood flow. This aspect will be studied with the use of the hydrogen clearance technique of Aukland. The maoaque monkey and dog will be used with the stereotaxic placement of thalamic and hypothalamic electrodes. Cortical and venous electrodes will be utilized as well. To this point, our evaluations of autoregulatory changes have involved only the influence of acute ethanolism. In the coming year, the scope of the work will be widened to include models with combined, acute, head injury. The specific forms of mechanical insult will be extradural balloon inflations and chiasmatic cisternal saline injections. Finally, CO2, reactivity will be tested in the combined setting.